The aim of this research is to demonstrate the anatomic substrate and neural basis for normal and abnormal eye movements in sub-human primates and in man. In this grant period we are investigating the neural basis for horizontal eye movements, the relationship between the oculomotor and visual systems, and changes in oculomotor function which occur after lesions of the central nervous system. Because of the similarity between the oculomotor systems of monkey and man, monkeys are generally used in these studies. Humans, cats or other species are studied when it is necessary to obtain comparative data. Eye movements are induced by visual or vestibular stimuli or by electrical stimulation of the peripheral or central nervous system. Eye movements are recorded by electro-oculography, by photo-electric oculography, or are photographed. Intracellular and extracellular unit activity and potential changes associated with eye movements are also recorded. Normal eye movements of monkeys and man are analyzed and compared before and after lesions in various parts of the nervous system. The anatomy of recording and lesion sites in monkeys is correlated with oculomotor and electro-physiological data. Findings in monkeys are compared wherever possible to those in humans. This research should lead to a better understanding of the normal and abnormal physiology of the oculomotor system. It should facilitate diagnosis and treatment of patients with disorders of the oculomotor, vestibular and body postural systems. It should also elucidate basic mechanisms of sensory-motor integration.